So how close to 40-55% humidity should I be?

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Altophile
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Re: So how close to 40-55% humidity should I be?

Post by Altophile » Fri Jan 12, 2018 3:08 am

I'm surprised at the figures being expressed here. When I read what humidity to keep my apt at for the sake of my guitar, the online article(s) said 30 to 60% is fine, but anything below or above is dangerous.

BellyDoc
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Re: So how close to 40-55% humidity should I be?

Post by BellyDoc » Fri Jan 12, 2018 5:13 am

Consistency is really helpful. Large fluctuations are probably a bigger threat than a modestly low humidity that’s otherwise stable. Change in humidity just insures that whatever potential there is for expansion and contraction is maximized in exactly the way that you don’t want it to be.

My home relative humidity varies from low/mid 30s to high 40s. I have an aquarium which probably helps. I keep guitars in a sealed second hand armoire I customized with a rock stable humidity of 43%. I really like having a cabinet because I can just open the door and shelve my guitar if I leave the room. It’s no more complicated than putting milk back in the fridge (now if I could just remember to put the milk away...)

The humidity stabilizer is a plastic bucket with a liter of saturated potassium carbonate solution and the evaporator from a small humidifier soaking it up.
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Michael.N.
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Re: So how close to 40-55% humidity should I be?

Post by Michael.N. » Fri Jan 12, 2018 8:15 am

Altophile wrote:
Fri Jan 12, 2018 3:08 am
I'm surprised at the figures being expressed here. When I read what humidity to keep my apt at for the sake of my guitar, the online article(s) said 30 to 60% is fine, but anything below or above is dangerous.
If the guitar was constructed at 50% RH 70% isn't going to kill it, 30% RH might. Too dry is far worse than too wet.
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Gustavosamor
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Re: So how close to 40-55% humidity should I be?

Post by Gustavosamor » Fri Jan 12, 2018 4:40 pm

I will say it is true that it is nearly impossible to keep an entire house between those humidity values, but that's why it is important to have that practice room where you also keep your guitar(s). It is easier to control in that way because if you take the guitar our to play a gig, the exposure to the dry air won't be longer than 2 hours. Also be careful with stage lighting systems!

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Re: So how close to 40-55% humidity should I be?

Post by richtm » Fri Jan 12, 2018 7:30 pm

I agree on the last statement, either you store your guitar in the case with some humidifier and hygrometer (as e.g. Eastman and other supplier offer it) or you store your guitar(s) in a small room that you are able to humidfy. I have no experience with cracked guitars, but I life in Hamburg which is a pretty wet are. Never the less we have in these winter days less than 40%rh so the humidifier is on to keep a humidity between 45% and 55% in my small office.
Some people report differences in sound of the guitar that is dry or humdified. I have not yet noticed any effect, but out of theory I can immagine that there should be one. :casque:
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fast eddie
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Re: So how close to 40-55% humidity should I be?

Post by fast eddie » Sun Jan 21, 2018 4:55 am

During this recent cold spell (of Jan 2018) I also could not get the RH in my practice room much above 38%. The outside temp has been about 20 deg. F. I used a room humidifier for an hour or so and the RH increased to about 40%. I wondered if having the guitar in the room while using the humidifier was a bad idea or not.
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Philosopherguy
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Re: So how close to 40-55% humidity should I be?

Post by Philosopherguy » Sun Jan 21, 2018 5:38 am

rpavich wrote:
Thu Jan 11, 2018 3:44 pm
Gustavosamor wrote:
Thu Jan 11, 2018 3:40 pm
Yes, it will be a really rare case if you guitar cracks with a high humidity, whereas the opposite is more likely to happen if you let it dries out.
Thanks, this is good to know. I'm going to look for a room humidifier also just to see if I can raise the humidity so that it's higher when the guitar is out of it's case.
I think you are overthinking this humidity stuff. If your room is between 37% and just over 40%, you have fairly ideal conditions there. I don't think you have too much to worry about. When you aren't playing, put the guitar in a case and keep it around 45% or so. With humidity above 35%, you won't have to worry about taking the guitar out and playing it for a few hours, or even longer. Guitars aren't that delicate. I prefer how my guitars sound when they are around 40% humidity. If you go much over that, I think guitars start to sound muddy.

You have had some pretty intense answers to some of your questions. Coming from Canada, where in the winter time our RH drops quite low, I don't worry too much. If guitars were that delicate we would never be able to bring them out of their temperature/humidity controlled environment to play concerts or experience playing in the outdoors.

Anything above 35% RH - not too much to worry about... At that humidity level, it would take quite a long time for the guitar to dry out and risk cracking. If your house was 10%, I might be more worried. But, anything above 35% is still in a very common range. Also, these mild fluctuations you talked about in your room are perfectly normal and shouldn't really do any damage either. You will learn what RH your guitar sounds best in and try to keep it around those values inside the case. Other than that, take it out as much as possible and enjoy it! You didn't buy the guitar to baby it and always worry about playing it!

Every once in a while I look over at my hygrometer and look where it's at and see if the house needs adjusting. Other than that, I don't worry too much. Back in my old house, the RH used to be in the 25% range sometimes and I still didn't have any issues. I just left the guitars in the case with a humidifier and brought them out and played them for a couple hours - no damage ever. I don't even use a great humidifier! Most of my cases have pill bottles with holes drilled in them with a damp sponge. Works good enough to satisfy me.

Just relax some and enjoy the new guitar!

Martin

PS. some of the answers that suggested keeping the guitar at 60 or 70%! Wow! I would start to worry about mould growing in the case at those levels.
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Michael.N.
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Re: So how close to 40-55% humidity should I be?

Post by Michael.N. » Sun Jan 21, 2018 10:15 am

No!! 60 to 70% RH is often seen indoors during the summer months here in the UK and a great many areas around the world. We aren't in mould inducing glue dissolving humidity at that level.
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Re: So how close to 40-55% humidity should I be?

Post by OldPotter » Sun Jan 21, 2018 1:56 pm

I've just checked the local weather and my own humidity indoors where my guitars are kept, it was 63% inside and the outside was 94%. I always keep my guitars on a stand and not in a case. The guitars are always fine and don't sound muffled. I did order a guitar from the USA several years ago and for the first couple of weeks it did sound muffled until it acclimatised. Its been fine ever since.
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soufiej
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Re: So how close to 40-55% humidity should I be?

Post by soufiej » Sun Jan 21, 2018 2:14 pm

This topic comes up often on guitar forums and I seldom see the correct answer.

The correct answer?

You're measuring the wrong thing.

A hygrometer in the vicinity of your guitar is only measuring the relative humidity in the air. What you are actually concerned with is the moisture content of the woods in your guitar. There can be a very large difference between the two values.

Anecdote time ... I have a friend who once owned a Mitsubishi Starion loaded with automation devices. This was back in the early 1980's and automation was still rather rare in most automobiles. We were headed over to Fort Worth one Sunday and as we cruised down the highway Pete hit the button for the instantaneous m.p.g. value.

"You are achieving 31 m.p.g.", said the automated female voice.

As we approached a small hill, Pete said, "Watch this." He gave the car some gas so we crested the hill going about 85 m.p.h. Headed down hill now, Pete took his foot off the gas pedal, shifted into neutral and let the engine free wheel. Next, he hit the same button to attain an instantaneous m.p.g. value.

"You are achieving 883 m.p.g.", said the female voice.

We both cracked up.

That's what your hygrometer is doing, giving you a number unrelated to the value you need to know.

The woods in your guitar retain moisture, lose moisture and then they take in moisture again. It's a continual process. That means on more humid days or under higher R.H. values the wood is seeking parity with the air. However, since R.H. is also tied to temperature, it is constantly fluctuating every time your H.V.A.C. system kicks on.

Remember, in the summer your A.C. cools the air by removing moisture also. Cool air holds less moisture so you will also have to monitor your guitar's condition year round.

When your hygrometer reads 35%, what's the moisture content of the spruce in your guitar? What about the mahogany or cedar in the neck? Every wood has a preferred moisture content and any guitar will have various pieces of wood used in its construction. (And, if your guitar has laminated back and sides, laminates are considered "environmentally stable" which means they do not expand and contract with R.H. the way solid woods do.)

A guitar can have a too high moisture content which, as noted, will also create stress problems with joints.

The best advice is to not be too concerned about R.H. levels. It will take several days in most environments for the wood to loose sufficient moisture even after your hygrometer has bottomed out. In the same manner, it will require several days for a too moist wood to loose its moisture. Unless you can constantly maintain the R.H. in the room at a specific value for several days, your guitar will be gaining or losing moisture constantly.

Play your guitar and become accustomed to its sound at different R.H. values. Don't get too concerned about what your hygrometer reads unless it hits extremes and stays there. 35% R.H. is not "extreme". Consistency over time is more important than any one reading. Be aware of the appearance of your guitar. Cracks typically appear first at joints between pieces of wood. Many cracks which appear from a too low moisture content will correct themself after proper moisture content has been returned. If you are familiar with the way your guitar sounds and looks, you are the best measurement tool you can have.

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Michael.N.
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Re: So how close to 40-55% humidity should I be?

Post by Michael.N. » Sun Jan 21, 2018 3:19 pm

No! That's nonsense. 'You are the best measurement tool that you can have' ? I mean seriously, what sort of advice is that? You wait until the crack appears and then you take action? That's what you seem to be suggesting.
We are measuring the correct thing in regards to guitars. RH has a direct bearing on the moisture content of the wood of our guitars. That's why if you allow the RH to drop extremely low then the chances of cracks increases enormously. Timber shrinks. Given that we are unlikely to stick probes into the wood of our guitars (to measure moisture content) we measure the RH in the atmosphere that our guitars live in. This is all standard stuff.
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Andrew Fryer
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Re: So how close to 40-55% humidity should I be?

Post by Andrew Fryer » Sun Jan 21, 2018 4:55 pm

Initially I was going to suggest that if you are comfortable, then your guitar will probably be comfortable.
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Michael.N.
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Re: So how close to 40-55% humidity should I be?

Post by Michael.N. » Sun Jan 21, 2018 5:56 pm

Well if you can reliably tell the difference between 50% RH and 25% RH unaided I guess you don't need an hygrometer. I'm not made of wood, so I've never been able to reliably tell the difference. Some people might be able to do that although I suspect they are in a minority.
This is simple. There's really no need to complicate things. You need a fairly accurate hygrometer. You need to know the RH that your guitar was constructed at. You need to keep your guitar within a reasonable figure of that RH - see my previous answer. Don't threat too much if it's out of that reasonable figure for a short period of time, the less time the better. Now it is quite possible that your guitar will survive very low RH for weeks and perhaps even months but make no mistake you are taking a risk. Given that it's neither too costly or that it requires mountains of effort to keep an instrument at a reasonable RH level the option is a simple one if you value your instrument. If you don't then you are free to do as you please.
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Andrew Fryer
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Re: So how close to 40-55% humidity should I be?

Post by Andrew Fryer » Sun Jan 21, 2018 6:16 pm

Michael.N. wrote:
Sun Jan 21, 2018 5:56 pm
I'm not made of wood
What do you think I'm made of, lasagne?

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Re: So how close to 40-55% humidity should I be?

Post by Rasputin » Sun Jan 21, 2018 7:30 pm

Michael.N. wrote:
Sun Jan 21, 2018 5:56 pm
You need a fairly accurate hygrometer. You need to know the RH that your guitar was constructed at. You need to keep your guitar within a reasonable figure of that RH...
It looks as though outdoor RH varies between about 70% and 90% in the UK, and yet people from warmer climates are saying they see about 60% as a maximum. Could this mean that it is absolute humidity that really matters? I haven't thought about the physics of it - at first blush it seems plausible that RH would equalise even if it meant large disparities in AH, the way temperature equalises even if it means large disparities in heat - but maybe it is more complicated than that.

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